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Discussion Starter · #1 ·
I have read two different TPS adjustment procedures. One is the fan on/off method and the other using volt meter.
When I do the fan method, I notice the RPM's jump up a little when I let off the throttle while driving. This is about .50 volt on volt meter.

I did the volt meter method and adjusted to around .60-.65 volt. The RPM jump is gone but, the fan is on when jumping TEN/GRND pins together. Does this mean the TPS is out of adjustment? Or does it matter if the fan is on at his adjustment?
 

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My knowledge is not very high on this issue but: from what I read, the voltmeter method is supposed to be more accurate. But there may not in fact be any real disagreement between the two methods in your case. Using the fan method, you adjust the tps unitl the fans are just on the knife-edge between being on and off. Since it's impossible to be exactly on that knife-edge (you have to be one side or the other) maybe the difference between the two methods is miniscule in your case. (Try just pressing the throttle back with your thumb, against the throttle stop screw. Maybe that will turn the fans off?)

I wouldn't worry about it, in any case, if the car drives fine. I tried both methods, before resorting to a third: trial and error. I adjusted the tps a little bit one way, then a little bit the other, until I felt the car drive best.
 

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I recently did the fan-type adjustment and my car has same symptoms as your's did. Plus stopping @ streetlights or for something else idle seems to set to different rpm's between about 600 to 1100rpm.
I'll try to finetune it with voltmeter.

Anyway, setting TPS got rid of most of the mysterious jerking the car had, which is a big :tup:
 

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The "voltmeter method" is a bunch of crap.

You absolutely must use the fan method to accurately set your TPS, because it also has an internal idle switch (this is why it has three wires and not two).

The idle switch should be set with the throttle closed, and you guessed it, in diagnostic mode, the fan comes on when the idle switch is tripped.


You must remember, that the ECU uses ranges to determine where you have the throttle (it's an 8 bit A/D conversion), not a smooth continuum. So, having it a few millivolts one way or the other makes absolutely no difference, unless your TPS is faulty. You should ideally have it set such that the idle switch just barely sets with your foot off of the accelerator pedal.


I suspect your "RPM jump" is due to a dirty IAC valve or possibly a faulty ECTS, which is also not used properly if the idle switch is not set.
 

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I wish I could answer your question, but it is unclear what "it" is referring to.
 

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snailman153624 said:
The "voltmeter method" is a bunch of crap.

You absolutely must use the fan method to accurately set your TPS, because it also has an internal idle switch (this is why it has three wires and not two).

The idle switch should be set with the throttle closed, and you guessed it, in diagnostic mode, the fan comes on when the idle switch is tripped.


You must remember, that the ECU uses ranges to determine where you have the throttle (it's an 8 bit A/D conversion), not a smooth continuum. So, having it a few millivolts one way or the other makes absolutely no difference, unless your TPS is faulty. You should ideally have it set such that the idle switch just barely sets with your foot off of the accelerator pedal.


I suspect your "RPM jump" is due to a dirty IAC valve or possibly a faulty ECTS, which is also not used properly if the idle switch is not set.
The voltmeter method is not a bunch of crap. But I agree that the 'voltage method' is wrong. You can still use a voltmeter to determine continuity, but the fan method does the same thing assuming your fans are working properly.
 

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Discussion Starter · #11 ·
My IAC is clean, just had throttle body off and took apart for cleaning. ECTS (what's this?) If it's a coolant sensor, both ('93 V6) are new. Can an improperly working TPS cause the slight jumping? I noticed my manual states about 5000 ohms at wide open throttle (don't recall which pins jumped together right now). I only get about 3,500 ohms at wide open throttle. Anyone shed any light on this?

BTW, these are some good posts on this topic. Thanks!


snailman153624 said:
The "voltmeter method" is a bunch of crap.

You absolutely must use the fan method to accurately set your TPS, because it also has an internal idle switch (this is why it has three wires and not two).

The idle switch should be set with the throttle closed, and you guessed it, in diagnostic mode, the fan comes on when the idle switch is tripped.


You must remember, that the ECU uses ranges to determine where you have the throttle (it's an 8 bit A/D conversion), not a smooth continuum. So, having it a few millivolts one way or the other makes absolutely no difference, unless your TPS is faulty. You should ideally have it set such that the idle switch just barely sets with your foot off of the accelerator pedal.


I suspect your "RPM jump" is due to a dirty IAC valve or possibly a faulty ECTS, which is also not used properly if the idle switch is not set.
 

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lakersfan1 said:
The voltmeter method is not a bunch of crap. But I agree that the 'voltage method' is wrong. You can still use a voltmeter to determine continuity, but the fan method does the same thing assuming your fans are working properly.
I agree the voltemeter can be used to check continuity and a smooth profile, but I don't think it should be used to set the TPS.
 

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jman said:
I have read two different TPS adjustment procedures. One is the fan on/off method and the other using volt meter.
When I do the fan method, I notice the RPM's jump up a little when I let off the throttle while driving. This is about .50 volt on volt meter.

I did the volt meter method and adjusted to around .60-.65 volt. The RPM jump is gone but, the fan is on when jumping TEN/GRND pins together. Does this mean the TPS is out of adjustment? Or does it matter if the fan is on at his adjustment?
I've had the surging and bucking at a steady speed and it was driving me nutz. But after reading this thread I tried setting the tps to .63 and I'll be darned if it didnt work great !! Thanks :D
 
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